By default, Xcode stores in a shared folder the derived data for all your projects. Derived data consists of project indexes, logs, and build products including intermediate build files.

If you specify an alternative drive for your derived data, the drive must be HFS+ formatted to support resource forks for code signatures.

If you choose to place derived data in a location relative to your projects and workspaces, be careful not to check in your derived data to source control management (SCM) systems. When performing backups or sending a copy of your workspace to someone else, be careful that you don’t inadvertently back up or send the derived data, which is often large and can always be re-created from the project sources.

To delete the derived data, choose Window > Organizer, and click Projects at the top of window. From the projects organizer that appears, click the Delete button for Derived Data.